1. Field of the Invention
This invention generally relates to an air conditioner and, more particularly, to an air conditioner with automatic selection and re-selection functions for operating modes.
2. Description of the Related Art
The so-called heat-pump type air conditioner now represents a major trend in air conditioners, being capable of operation in both cooling and heating modes.
Some conventional air conditioners have an automatic mode selection opeation function for comparing a current room temperature with a preset reference temperature and for automatically selecting one of "cooling", "dehumidifying", "blowing", and "heating" operating modes, based on the comparison result. According to one mode selection control method of such a conventional air conditioner, a current room temperature is detected at the beginning of an automatic mode selection operation and the detected value is compared with the corresponding reference value so as to determine the appropriate operating mode. Thereafter, the mode is left unchanged, unless an operation stop instruction is supplied.
According to another mode selection control method, the current room temperature is continuously compared with a set reference value in order to change operating mode if and as required.
When the former control method is employed, the operating mode cannot be changed even if a load such as the room temperature or room humidity varies after commencement of the selected operation mode. In such a case, the air conditioner continues operating in what has now become an inappropriate mode, thus creating discomfort for the occupants of the room being air conditioned. On the other hand, when the latter control method is employed, if the room temperature increases/ decreases even slightly in relation to the reference temperature, the operating mode will likely alternate unnecessarily frequently from one mode to another, thereby resulting in inconsistent temperature of the room and, as before, discomfort for any occupant of the room.
As has been described above, according to the air conditioner having a conventional automatic mode selection operation function, user comfort can be a problem, as an appropriate operating mode cannot easily be selected automatically to suit any change in load. As a result, there is now demand for an air conditioner device having an improved automatic mode selection function.